1. Technical Field
The present invention relates to a multilayered printing material. Accordingly, a printing material is provided with a carrier layer and with at least one one-sided self-adhesive, printable layer which rests with its self-adhesive surface on a supporting surface of the carrier layer in an adhering manner, and which is again detachable from the supporting surface and has at least one printable surface. In addition, the present invention relates to the use of the printing material.
2. Description of Related Art
Goods to be shipped frequently require immediate labeling. In the food industry, for example, shipping of foods such as frozen products must be monitored and controlled using electronic devices. Data required for shipping and data identifying the product is typically retained on such a label. Measuring data memory devices are specially provided for this purpose, from whose memory the respective data is read out on site and is printed onto the particular labels. For proof of proper transportation and the condition of the product, the label is subsequently applied directly to the product or to a container accommodating the products.
For this purpose, there are basically two different labeling mechanisms:
The continuous paper used for labeling is not self-adhesive and for this reason may only be applied to the merchandise by using an adhesive film, glue, or the like. However, due to the additionally required attaching means, such a method is extremely expensive and is also difficult to be automated, resulting in significant extra costs.
In addition, self-adhesive continuous paper, composed of a carrier film and a printing paper adhering thereto, may also be used. The printing paper has an adhesive film and may thus be applied directly to the merchandise to be shipped without any extra application. Here, the process is made easier for the user, which in turn makes this form of labeling more advantageous compared to the first method, in particular with regard to costs.
Thermal printers which are suitable for printing paper, cardboard, foil, etc., are used for printing on such a self-adhesive continuous paper. The printing unit of the thermal printer has, as a rule, one or more thermal print heads which cooperate with a print roller in order to print the continuous paper passing through the printing unit.
However, printing of self-adhesive continuous paper using a thermal printer has several practical and technical disadvantages:
Self-adhesive continuous paper may not be inserted into printing units of common printers; it is in fact only suitable for particular special printer variants. A single type of paper is frequently only usable in such special printer variants; the same manufacturer of the special printer variants mostly distributes this paper. Understandably, this paper is much more expensive than common self-adhesive continuous paper. In addition, the handling of the printing units of the particular special printer variants is very laborious since the continuous paper has to be threaded into the printing unit in a time-consuming manner. Since there is only a relatively small number of printers available on the market which can communicate with a measuring data memory device, and which, for the purpose of printing out measuring data, are equipped with such a special printing unit for printing and transporting self-adhesive continuous paper, the user is practically forced to use such a printer and with it also the appropriate and more expensive paper.
However, the self-adhesive and printable continuous paper used in such printers has a serious disadvantage which is explained in the following based on FIG. 6:
Self-adhesive continuous paper 20, used in practice, is typically wound up on a roll and is composed of two layers 21, 22. First layer 21 is the carrier foil and second layer 22 is the self-adhesive thermal paper. Carrier paper 21, adhering with a surface 26 to backside 23 of self-adhesive thermal paper 22, protects adhesive layer 27 of thermal paper 22. Due to the fact that continuous paper 20 is wound up on a roll and thus the inner of the two layers, typically the carrier foil, always has a smaller diameter than the outer layer resting thereon, the inner layer in its wound-up state is shorter than the outer layer.
If this continuous paper 20 is inserted into a conventional printing unit 10 of a thermal printer, then, as a consequence of deflecting continuous paper 20 in connection with the particular pressure acting against pressure rollers and conveyor rolls 12–14, squeezing of both layers 21, 22 takes place, resulting in the separation of thermal paper 22 from carrier foil 21. Due to the temporary separation of both layers 21, 22 from one another, a length adjustment of the originally wound-up paper takes place which devolves into the straight after passing through printing unit 10. Since the same length of both carrier paper 21 and thermal paper 22 passes through printing unit rolls 12–14, this length excess of the thermal paper accumulates upstream from printing unit rolls 13, 14 and increases as the printing process proceeds. If the length excess of thermal paper 22 becomes too great, then printing unit 10 may no longer properly convey continuous paper 20. This conveyance interruption frequently results in illegible misprints. Thus, the merchandise to be shipped may no longer be labeled in the proper form. This has serious consequences if such a misprint is applied to the merchandise to be labeled and is detected either very late or not at all. In this case, the merchandise mostly may not be shipped due to the absence of the required data. In addition, retroactive proof of the data required for this merchandise, e.g., the best-before date, is no longer possible.
Understandably, these errors caused by incorrect label printing should be avoided.
Therefore, it is desirable to provide a printable and self-adhesive continuous paper which avoids misprints to the greatest possible extent. Moreover, the continuous paper should not be limited to special printer variants.